Today in Europe many mattresses that are sold commercially are made with foam inner cores. In such mattresses, the interior main body that provides support to the user is a block of foam that is sufficiently soft yet supportive to provide a comfortable sleep.
An alternative common type of mattress has an inner spring assembly formed of spring coils that provide a resilient support surface for the user. Spring coil mattresses can be open coil or Marshall that provide a durable high quality mattress product.
In recent years, certain new products have been developed that combine both foam core mattresses with inner spring assemblies to provide foam mattresses that have spring coils incorporated within the foam core. In one example, a foam block is provided that can act as the mattress core. A set of bore holes are formed into the foam block either by drilling or molding, but in either case, the bore holes are configured to receive spring coils that can be placed therein. Typically, the spring coils are dimensioned to fit within the bore holes so that the top of the spring coil is at the same height as the top of the foam core. In this way, the resultant mattress has the benefits of both a foam core mattress and a spring coil mattress. In other products, channels are cut into the foam to provide a trough in which spring coils, including Marshall spring coils, can be disposed.
Although these combination mattresses provide many benefits, the process of actually forming a foam core mattress that can receive spring coils either through bore holes or channels is complicated and costly. Accordingly, there is a need in the art for improved methods for manufacturing foam cores, and in particular for manufacturing foam cores that have spaces or voids into which additional components may be fitted.